[PATCH v1 2/2] rtc: loongson: Add Loongson-2K0300 support

Binbin Zhou
2025-12-23T06:42:39Z

The Loongson-2K0300's rtc hardware design is similar to that of the
Loongson-1B, but it does not support the alarm feature.

Introduce `LOONGSON_RTC_ALARM_WORKAROUND`, which indicates a chip that
does not support the alarm function, and rewritethe related logic in
`loongson_rtc_alarm_setting()`

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
---
drivers/rtc/rtc-loongson.c | 65 ++++++++++++++++++++++++++------------
1 file changed, 44 insertions(+), 21 deletions(-)

diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
index 2ca7ffd5d7a9..6b076bd4e24e 100644
--- a/drivers/rtc/rtc-loongson.c
+++ b/drivers/rtc/rtc-loongson.c
@@ -67,6 +67,7 @@
* Accessing the relevant registers will cause the system to hang.
*/
#define LS1C_RTC_CTRL_WORKAROUND BIT(0)
+#define LOONGSON_RTC_ALARM_WORKAROUND BIT(1)

struct loongson_rtc_config {
u32 pm_offset; /* Offset of PM domain, for RTC alarm wakeup */
@@ -89,7 +90,7 @@ static const struct loongson_rtc_config ls1b_rtc_config = {

static const struct loongson_rtc_config ls1c_rtc_config = {
.pm_offset = 0,
- .flags = LS1C_RTC_CTRL_WORKAROUND,
+ .flags = LS1C_RTC_CTRL_WORKAROUND | LOONGSON_RTC_ALARM_WORKAROUND,
};

static const struct loongson_rtc_config generic_rtc_config = {
@@ -97,6 +98,11 @@ static const struct loongson_rtc_config generic_rtc_config = {
.flags = 0,
};

+static const struct loongson_rtc_config ls2k0300_rtc_config = {
+ .pm_offset = 0x0,
+ .flags = LOONGSON_RTC_ALARM_WORKAROUND,
+};
+
static const struct loongson_rtc_config ls2k1000_rtc_config = {
.pm_offset = 0x800,
.flags = 0,
@@ -299,9 +305,41 @@ static const struct rtc_class_ops loongson_rtc_ops = {
.alarm_irq_enable = loongson_rtc_alarm_irq_enable,
};

+static int loongson_rtc_alarm_setting(struct platform_device *pdev, void __iomem *regs)
+{
+ int ret = 0, alarm_irq;
+ struct device *dev = &pdev->dev;
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ if (priv->config->flags & LOONGSON_RTC_ALARM_WORKAROUND) {
+ /* Loongson-1C/Loongson-2K0300 RTC does not support alarm */
+ clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
+ return 0;
+ }
+
+ /* Get RTC alarm irq */
+ alarm_irq = platform_get_irq(pdev, 0);
+ if (alarm_irq < 0)
+ return alarm_irq;
+
+ ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr, 0, "loongson-alarm",
+ priv);
+ if (ret < 0)
+ return ret;
+
+ priv->pm_base = regs - priv->config->pm_offset;
+ device_init_wakeup(dev, true);
+
+ if (has_acpi_companion(dev))
+ acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
+ loongson_rtc_handler, priv);
+
+ return ret;
+}
+
static int loongson_rtc_probe(struct platform_device *pdev)
{
- int ret, alarm_irq;
+ int ret;
void __iomem *regs;
struct loongson_rtc_priv *priv;
struct device *dev = &pdev->dev;
@@ -330,25 +368,9 @@ static int loongson_rtc_probe(struct platform_device *pdev)
return dev_err_probe(dev, PTR_ERR(priv->rtcdev),
"devm_rtc_allocate_device failed\n");

- /* Get RTC alarm irq */
- alarm_irq = platform_get_irq(pdev, 0);
- if (alarm_irq > 0) {
- ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr,
- 0, "loongson-alarm", priv);
- if (ret < 0)
- return dev_err_probe(dev, ret, "Unable to request irq %d\n",
- alarm_irq);
-
- priv->pm_base = regs - priv->config->pm_offset;
- device_init_wakeup(dev, true);
-
- if (has_acpi_companion(dev))
- acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
- loongson_rtc_handler, priv);
- } else {
- /* Loongson-1C RTC does not support alarm */
- clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
- }
+ ret = loongson_rtc_alarm_setting(pdev, regs);
+ if (ret)
+ return ret;

/* Loongson RTC does not support UIE */
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, priv->rtcdev->features);
@@ -379,6 +401,7 @@ static const struct of_device_id loongson_rtc_of_match[] = {
{ .compatible = "loongson,ls1b-rtc", .data = &ls1b_rtc_config },
{ .compatible = "loongson,ls1c-rtc", .data = &ls1c_rtc_config },
{ .compatible = "loongson,ls7a-rtc", .data = &generic_rtc_config },
+ { .compatible = "loongson,ls2k0300-rtc", .data = &ls2k0300_rtc_config },
{ .compatible = "loongson,ls2k1000-rtc", .data = &ls2k1000_rtc_config },
{ /* sentinel */ }
};
--
2.47.3